1. Technical Field
The invention relates to the field of assembling structural components together by clipping them together.
The invention relates more particularly to a fastener device for assembling a part to a support portion, said fastener device comprising a fastener clip including a head and a deformable catch element that extends under the head in an axial direction, and that defines a cramping face spaced apart from the head in said axial direction, said catch element being designed to be pushed through the part and through the support portion in such a manner as to achieve assembly by cramping the part and the support portion between the head and the cramping face of the clip, said catch element being designed in such a manner that said cramping face is retracted resiliently into the clip transversely to said axial direction when the catch element is pushed through the part and through the support portion until the clip is pushed fully through the support portion, the cramping face returning resiliently to outside the clip so as to take up a cramping position for cramping to the support portion whenever the catch element is in said fully pushed-in position.
2. Prior Art
Such a fastener device is known from Patent Document DE-10 2011 010 141. That known clip fastener device is shaped in the form of a channel-section member so as to have high rigidity and so as to have high mechanical resistance to being torn out.
It is well suited to assembling an airbag to a motor vehicle steering wheel.
In the automobile industry, fastener devices that use clipping are increasingly replacing assembly systems that use nuts and bolts.
Where the problem of safety is important, such as, for example, for fastening an airbag to a fixed component of a motor vehicle, it is essential to ensure that the quality of the fastening provided by a clip fastener does indeed comply with the requirements relating to strength.
However, with clip fastener devices, it is often not simple to determine whether the device has been correctly fastened, or whether it has, for example, remained in a semi-locked state.
In many situations, e.g. when assembling an airbag to a steering wheel, establishing whether the device has been correctly fastened is made even more difficult by the fact that it is very difficult to check the states of clip fastener devices by visual observation.
Patent Document DE-10 2004 025 698 also discloses a fastener device for fastening together two structural elements by clipping that is made up both of a clipping element that can take up an engaged thrust position, and a cramping catch position, and also of a proper-assembly indicator for checking that assembly has been achieved properly. In that fastener device, the catch element and the proper-assembly indicator are coupled together in the engaged thrust position and are arranged in such a manner that movement of the proper-assembly indicator relative to the catch element in the checking direction is possible only if the catch element is in its cramping catch position.
It is thus possible to check that the structural elements are properly assembled together merely by trying to move the proper-assembly indicator in the checking direction. If such a movement is possible, that indicates that the structural elements have been properly assembled together. If that movement is not possible, that indicates that the catch element is not properly pushed into the structural elements and that it is not in a cramping catch position.
Patent document EP 2 687 731 also discloses a fastener device for fastening together two structural elements by clipping with a proper-assembly indicator for checking that assembly has been achieved properly.